var as = document.getElementById("box_t").getElementsByTagName("a");
				var box_bot = document.getElementsByClassName("box_bot");
				    for(var i = 0;i<as.length;i++){
				    as[i].index = i;
				    as[i]. onclick= function(){
				        for(var j = 0;j<as.length;j++){
				          as[j].className = "";
				        }
				        this.className = "active";
				        for(var i=0;i<box_bot.length;i++){
            				box_bot[i].style.display = "none";
        			}				
        				box_bot[this.index].style.display = "block";        
				  }
				 }